Hi Guys,
according to Rei size charts (http://www.rei.com/sizefinder/footwear.html)
they are a UK 11, US 11.5
Very comfy, superb stable support (I used them with DMM Terminator crampons at Giants and Sani Pass ice climbing).
They have been used on 2 occasions, so practically brand new, solid and great quality (as you would expect from La Sportiva)